Whitepaper · Eye care · System conversion
The cash dip after a system switch is planned in advance, or it is not avoided.
When an eye group changes its EHR or practice management system, cash usually falls for reasons that are known months ahead: charges posted late, remittances not posting, claims held on new edits, and old A/R left to age. This is the cutover plan that keeps cash flat.
By ASP-RCM Editorial, Healthcare RCM Practice · Updated
The question for your conversion team
Who owns the old system's A/R on the morning after go-live, and what is their daily target?
Charge lag, the first KPI to watch
HFMA MAP Key: days from date of service to charge posting
Medicare filing limit
From date of service (42 CFR 424.44); legacy claims keep their clock
Medi-Cal billing limit
Original claims after the month of service, for full payment
Watch window after go-live
Daily and weekly KPIs against your own pre-conversion baseline
Where the cash goes during a conversion
Charge lag
Providers and techs learn new screens. Charges post days later, so claims go out later.
Posting backlog
ERAs fail to load or route to the old system. Payments sit unposted and denials go unseen.
Claim holds
New scrubber edits, missing payer IDs or provider mappings stop claims before they leave.
Legacy A/R run-out
Old balances stop being worked because the team is busy with the new system. They age toward filing limits.
Payer enrollments that change with a new system
Start these early. Each payer and clearinghouse sets its own processing time.
| Item | When it changes | What to do |
|---|---|---|
| Medicare EDI enrollment | New clearinghouse or billing service submitting claims | CMS requires the EDI Enrollment Form before electronic claims, whether sent directly or through a clearinghouse |
| Electronic remittance (835) routing | ERAs must go to the new system or clearinghouse | Notify each payer of the new receiver. Medicare's EDI form requires notice of changes to third parties authorized to get remittances |
| EFT (CMS-588 for Medicare) | Only if the bank or account changes | CMS says a new CMS-588 is needed for account changes, not on a schedule. One form can cover multiple PTANs |
| Commercial, MA and IPA submitter IDs | New clearinghouse or payer portal access | Re-enroll each payer for 837, 835 and 270/271 eligibility under the new submitter |
| Medi-Cal and Medi-Cal plans | New submitter or new remittance receiver | Update each with the plan or the state's EDI process before go-live |
Crosswalks an eye group must build and test
| Crosswalk | Eye-specific risk |
|---|---|
| Providers, locations and billing IDs | Dozens of providers across sites; a wrong location or NPI pairing fails enrollment edits |
| Payer list and payer IDs | Plans, IPAs and vision plans with similar names; DOFR routing must carry over |
| Fee schedules and contracts | Contract-expected amounts are needed from day one to catch short pays |
| Charge codes and modifiers | Laterality, eyelid and same-day modifiers, eye codes vs E/M defaults |
| Drug codes, units and NDCs | Retina drug units, NDC and JW or JZ must map exactly, or high-dollar lines deny |
| Adjustment and denial codes | CARC and RARC mapping drives denial worklists. See the 835 to appeal routing guide |
Cutover plan
Timing below is a planning default. Move it earlier for any payer with a slow enrollment process.
- 120 days out
Enrollment and EDI. File clearinghouse, ERA and submitter changes with every payer. Freeze the provider and location list.
- 60 days out
Crosswalks built. Payers, fees, charge codes, drugs, adjustment codes. Measure your baseline KPIs.
- 30 days out
Test claims and test ERAs with your top payers by volume. Work down open legacy holds.
- Go-live
New charges in the new system only. Legacy A/R stays in the old system with a named team.
- Days 1 to 30
Daily watch. Charge lag, claims held, ERAs posted, rejections by payer.
- Days 31 to 90
Weekly watch. Cash, denials, A/R aging and legacy run-out against baseline.
Legacy A/R: run it out, or convert it?
Most groups run out the old balances in the old system. Converting balances moves risk into the new system on day one.
Convert open balances
- Payments for old claims arrive with old claim numbers
- Corrected claims and appeals need the original history
- Balance errors land in the new system at go-live
Run out in the old system
- Keep the old system live for posting and follow-up
- Assign a team with a daily target to work legacy A/R by filing deadline
- Move only small residual balances after the run-out period
Filing limits do not pause for a conversion
Medicare
One calendar year from the date of service (42 CFR 424.44).
Medi-Cal fee-for-service
Six months after the month of service for full payment, with reduced payment or denial after that.
California plans and IPAs
Contract limits cannot be shorter than 90 days from service for contracted providers, or 180 days for non-contracted.
Go-live week, day by day
Charges
Every site reports unposted visits by end of day. Lag above baseline gets same-day help.
Claims
Review held and rejected claims twice a day. Fix the mapping, not just the claim.
Remittances
Confirm every expected ERA arrived and posted. Missing files go to the clearinghouse that day.
Denials
Sort new-system denials by cause. A spike in one code usually means one crosswalk error.
Legacy
Run-out team reports dollars worked and collected daily.
90-day monitoring metrics
Use HFMA MAP Key definitions and compare to your own baseline from the 90 days before go-live.
| Metric | Definition | Watch for |
|---|---|---|
| Total charge lag days (PB-4) | Days from service to charge posting, per charge code | Any site above its baseline |
| Late charges as % of total (CL-2) | Charges posted more than 3 days after service / total charges | A rising share in weeks 1 to 4 |
| Days in final billed not submitted (PB-2) | Billed but not yet sent to payer / average daily gross revenue | Claims stuck on new edits |
| Clean claim rate (CL-1) | Claims passing edits with no manual touch / claims accepted | Drops that point to a crosswalk |
| Remittance denial rate (AR-5) | Claims denied / claims remitted | New denial codes by payer |
| Cash collection as % of NPSR (FM-2) | Cash collected / average monthly net patient service revenue | A dip below baseline after week 3 |
| Aged A/R as % of billed A/R (AR-1) | A/R in each aging bucket / total billed A/R | Legacy balances moving past 90 and 120 days |
Worked example: one site, one clinic day not billed
Illustration, not a client result. Hypothetical day of 20 exams, 15 injections and 15 OCTs, priced at CY2027 national Medicare office amounts, drugs excluded.
National amounts from CMS-1848-F Addendum B times $32.6286. Drug lines, which often exceed these totals, are excluded. Multiply by sites and days of lag to size the risk.
Is your conversion plan built around cash?
A conversion cash dip comes from four known causes. File payer changes early, test the crosswalks with real claims, keep a named team on legacy A/R, and watch charge lag, holds, ERAs and denials daily for 30 days. Measure against your own baseline. See the multi-site ophthalmology playbook for the lane owners.
Questions operators ask next
Why does cash drop after an EHR or practice management conversion?
Usually four reasons. Charges post later while staff learn the new system. Remittances fail to load, so payments and denials go unposted. New edits and missing payer or provider mappings hold claims. And old A/R stops being worked. Each can be planned for with early payer enrollment, tested crosswalks and a legacy A/R team.
Do I need a new Medicare EFT form when switching systems?
Not usually. CMS says a new CMS-588 is needed only when account information changes or CMS revises the form, and one form can cover multiple PTANs. A new clearinghouse or billing service does need the Medicare EDI enrollment, and changes to who receives your electronic remittances must be reported to the Medicare contractor.
Should we convert old A/R balances into the new system?
Most groups run out legacy A/R in the old system, because late payments, corrected claims and appeals need the original claim history. Keep the old system available for posting and follow-up, give a named team a daily target ordered by filing deadline, and move only small residual balances after the run-out period.
What KPIs should we watch after go-live?
Watch total charge lag days, late charges, days in final billed not submitted, clean claim rate and remittance denial rate daily or weekly for the first 30 days. Add cash collection as a percent of net patient service revenue and aged A/R through day 90. Use HFMA MAP Key definitions and compare to your own pre-conversion baseline.
Plan your eye group's conversion around cash, not just go-live.
Tell us your go-live date and payer mix. A senior eye care revenue cycle lead walks your team through enrollment lead times, crosswalk gaps and a 90-day cash watch list, in a free 30-minute call with a written cutover checklist after.
Keep reading
Sources
- CMS, How to Enroll in Medicare Electronic Data Interchange
- CMS, EDI Enrollment Form
- CMS, National Provider Enrollment Conference FAQs (CMS-588 EFT)
- HFMA, MAP Keys: industry-standard revenue cycle KPIs
- eCFR, 42 CFR 424.44, time limits for filing claims
- Medi-Cal Provider Manual, Claim Submission and Timeliness Overview
- DMHC, Claims Technical Assistance Guidance, January 2026 (28 CCR 1300.71(b)(1))
- CMS, CY2027 PFS final rule CMS-1848-F, Addendum B
Checked November 6, 2026. Cutover timing is a planning default, not a rule. Payer enrollment rules from CMS, DHCS and DMHC public pages checked today. No vendor is named or endorsed. General information, not legal advice.